1. Field of the Invention
The present invention relates to a therapeutic support for the human body; and, more particularly, to a therapeutic support such as a seat or a bed that aids in the healing of decubitus ulcers and reduces the likelihood of formation of such ulcers.
2. Description of the Related Art
It is well known that non-ambulatory or partially immobile people who are confined to beds, chairs, wheelchairs, and the like may suffer from the formation of decubitus ulcers, also known as pressure ulcers, pressure sores, and bedsores. Decubitus ulcers are generally formed by a reduction or absence of capillary blood flow in the sufferer""s skin. For a non-ambulatory or partially immobile person, the reduction or absence of capillary blood flow is primarily caused by the weight-bearing bony protrusions compressing the skin against a support such as a bed or wheelchair, with the person remaining in the same position for an extended period of time. The compression of the skin by the weight-bearing bony protrusion reduces or stops the capillary blood flow in that area of the skin, leading to necrosis and the formation of a decubitus ulcer.
The formation of a decubitus ulcer is exacerbated by the existence of moisture from perspiration or incontinence, for example, which are often associated with non-ambulatory or partially immobile persons.
For a person who uses a wheelchair, the coccyx and ischials are the principal weight-bearing bony protrusions, and the adjacent areas of skin are the most likely locations for the formation of decubitus ulcers. Previous wheelchair seat designs have not adequately addressed the therapeutic need for relieving pressure on the person""s skin in the coccyx and ischial areas to reduce the likelihood of decubitus ulcers.
In the case of a person constrained to spend long periods in a bed, the areas of the coccyx and ischials remain a problem, but problem areas also include, without limitation, the heels, ankles, shoulder blades, elbows and wrists.
The invention is a therapeutic support such as a seat or bed that reduces the likelihood of the formation of a decubitus ulcer. Preferably, the therapeutic seat or bed prevents the extended loss or reduction of capillary blood flow to the weight-bearing areas of a seated or reclining person. Additionally, the therapeutic support provides for the removal of moisture from the weight-bearing areas. A therapeutic seat or bed according to the invention is capable of performing these functions individually or in combination.
More particularly, the invention provides such a therapeutic support which includes a cushion sized to support one or more bony protrusions or weight-bearing areas of a body placed in contact with its upper surface and formed with at least one cell cell cavity at a location respectively corresponding to one of the weight-bearing portions of the body. A compressible cell is received in the cavity. The cell has a configuration complementary to the cavity in which it is received. Preferably, the therapeutic support has multiple cavities with a corresponding number of cells. At least one cell is associated with such weight-bearing area supported by the seat. There can be multiple cells associated with one or more of the weight-bearing areas.
Each of the cells is compressible from a relaxed state to a compressed state. When a cell is in the relaxed state, its upper surface portion is preferably substantially at the height of the upper surface of the cushion. When a cell is in its compressed state, its upper surface portion is preferably lower than the upper surface of the cushion. Thus, when any one of the cells is in its relaxed state, the upper surface of the cushion and the upper surface portion of that cell form a substantially continuous surface for supporting the non-weight-bearing areas of the body and the weight-bearing area corresponding to that cell. When, on the other hand, any one of the cells is in its compressed state, pressure on the corresponding weight-bearing area is reduced.
In an alternative construction, the support can include a base one which the cells are supported. The base can, but need not, have a cushion. The base includes hollowed portions fluidly connecting some of the cells to define cell subsets whose state are changed concurrently to form zones. Preferably, each zone is associated with a different weight-bearing area and each zone is independently controlled.
In a preferred construction, each of the cells comprises a resilient compressible core and a flexible bladder enveloping the core. One end of a fluid conduit extends into the bladder so that when a negative pressure is applied to the conduit, fluid in the bladder is drawn out to contract the bladder and thus compress the core.
Other features and advantages of the invention will be apparent from the ensuing description in conjunction with the accompanying drawings.